Method for monitoring components of a cooling system in a rolling mill, computer program, and cooling system

Abstract

The present invention relates to a method and a computer program for monitoring components of a cooling system in a rolling mill. The cooling system, including the components, is used to apply coolant to a rolled product to be cooled. To ensure that coolant can be applied to the rolled product at a desired target pressure or volumetric flow rate not only in the new state of the components but also in the used state of the components, the cooling system according to the present invention provides for the acquisition of actual characteristic data of the components during and / or after their operating time. This actual characteristic data is compared with predetermined target characteristic data, as the case may be, to determine a deviation Δ of the characteristic data relative to the new state of the components, which may indicate a malfunction of the components. Furthermore, the present invention provides various measures for minimizing the characteristic data deviation if the characteristic data deviation exceeds a predetermined threshold.

Description

[Technical Field]

[0001] The present invention relates to a method and a computer program for monitoring components of a cooling system in a rolling mill, the cooling system including the components being used to apply a coolant to a rolled product to be cooled. Furthermore, the invention also relates to a corresponding cooling system. [Background technology]

[0002] prior art Known cooling systems in rolling mills essentially consist of a cooling section with multiple spray nozzles to which coolant is supplied via a system of pumps and valves. The coolant is preferably supplied to the spray nozzles at the required pressure. For this purpose, the coolant is held in an elevated tank and / or the required pressure is generated by one or more pumps. Generally, known cooling systems typically include a control device or regulating circuit with an actuator for setting or adjusting the actual pressure or volumetric flow rate at which the coolant is applied to the rolled product to be cooled. In this case, various components of the cooling system, such as pumps, valves, or the spray nozzles themselves, are used as actuators. The aforementioned control device or regulating circuit offers the advantage of dynamic and precise application of coolant at the desired target pressure or target volumetric flow rate. The use of a speed-controlled pump allows the pressure loss, and thus the energy loss, generated by the aforementioned actuators in the cooling system to be kept as low as possible.

[0003] Several publications address the above-mentioned control and regulation, as well as the optimization of such control and regulation. One such publication is U.S. Pat. No. 5,629,499. This publication describes an operating method for a cooling line for cooling a hot-rolled metal product, in which the cooling line includes a pump that draws coolant from a coolant reservoir and supplies it to multiple coolant outlets via a line system controlled by valves located upstream of the coolant outlets. A control device for the cooling section periodically performs the following steps: Considering the coolant flow rate to be discharged through the coolant outlets at each time, the control state of the valve is determined in conjunction with the operating pressure of the cooling water on the inlet side of the valve; The total coolant flow rate is determined by summing the coolant flow rates; Considering the total coolant flow rate and the operating pressure of the coolant, the pump pressure to be applied on the inlet side of the pump is determined, so that the operating pressure is achieved on the inlet side of the valve; The control state of the pump is determined by considering the total coolant flow rate, pump pressure, and suction pressure on the inlet side of the pump; The valve and pump are controlled according to the determined control state. In order to be able to provide the required amount of coolant with high accuracy at any time in an inefficient manner, even if there is no storage option for coolant between the pump and the coolant outlet, the control device periodically takes into account changes in the total coolant flow rate in addition to the total coolant flow rate and the coolant operating pressure at each point in time when determining the pump pressure.

[0004] Despite this prior art, it is common to record a calibration characteristic curve for the actuator when the cooling system is first put into operation so that the actuator's operating point can be quickly adjusted later. The calibration characteristic curve, also called the base characteristic curve, is the actuator's target characteristic data, which preferably describes the calibrated behavior of the actuator under wear-free and error-free conditions during wear-free and error-free operation of the cooling system. In reality, over time, the actuator and the system in which it operates can become contaminated, deposits, corrosion, and wear. It is also possible for the outlet openings of the spray nozzles to become clogged, making it impossible to adjust the maximum cooling water volume. Uniform cooling of the rolled product across the width of the table is no longer possible, which can lead to quality losses during production.

[0005] All of these above-mentioned negative changes in the actuator or in the actuator's surrounding environment are traditionally captured in so-called system characteristic curves, which may change over the course of the cooling system's operating time. The term "changes in the system characteristic curve" will be used below as a synonym for the above-mentioned negative changes.

[0006] Therefore, for the correct setting or current configuration of components or actuators in the cooling system, it is necessary to know the current operating characteristic curve of the cooling system, which results from the superposition of the system characteristic curve and the basic characteristic curve (see lecture script "Measurement Technology, Control Technology and Regulation Technology", Institute of Process Engineering, University of Linz, Walser Straße 42, 4060 Leonding / A).

[0007] Manual status monitoring of a cooling system can usually only be performed when the system is shut down and is usually very labor intensive, especially at the typical scale of cooling lines in a rolling mill with multiple actuators to be monitored for cooling line status. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] European Patent Application Publication No. 3495056 Summary of the Invention [Problem to be solved by the invention]

[0009] The object of the present invention is to further improve known methods and computer programs for monitoring components of a cooling system in a rolling mill, as well as corresponding known cooling systems having components for applying coolant to a rolled product to be cooled, in such a way that the coolant is always applied to the rolled product to be cooled at a desired target pressure or a desired target volumetric flow rate, even if the system characteristic curve changes over time. [Means for solving the problem]

[0010] This problem is solved by the method described in patent claim 1.

[0011] The object of the present invention is to establish preferably continuous status monitoring of cooling system components or actuators in a rolling mill. The method provides for the determination of actual characteristic data of the components during and / or after the operating time of the cooling system components or actuators, which are then compared with previously determined or predetermined target characteristic data for the components. In this case, the actual characteristic data represents or includes the actual state of the components in their surrounding environment, including all possible negative changes. Meanwhile, the target characteristic data represents the components and their surrounding environment in a fault-free, particularly wear-free, state. This comparison allows for the determination of adjustments to characteristic data that may represent or indicate a malfunction of the components. The method then provides for minimization adjustment measures to be taken if characteristic data deviations exceed a predetermined threshold. The actual characteristic data determined for the components and their comparison with the target characteristic data of the components allows for conclusions to be drawn about the wear state of the components. This allows for the determination of reliable data for maintenance and servicing. In this way, production time at the rolling mill can be increased by avoiding unplanned system interruptions during production operations and by deferring maintenance operations until a planned maintenance shutdown.

[0012] According to a first embodiment, the means for minimizing characteristic data deviations can alert or indicate to the cooling system operator or reporting system to inspect each component and repair or replace as necessary.

[0013] Additional or alternative measures for minimizing characteristic data deviations may include: variable switching of characteristic data deviations or correction values ​​calculated from characteristic data deviations as disturbance variables in the sense of disturbance variable switching to a control device or controller in order to determine corrected manipulated variables and output the corrected manipulated variables to the component at the output of the control device or controller, which allows better consideration of system characteristic curves that have changed over time when controlling the component.

[0014] According to another measure, alternatively or additionally, the characteristic data deviation or a correction value calculated therefrom can also be applied as a disturbance variable to a setpoint setting device, which is typically connected upstream of the control device or controller, where the applied characteristic data deviation or the applied correction value calculated therefrom is then used in the setpoint setting device for adjusting in accordance with a setpoint value for the control device or controller.

[0015] According to a further embodiment, at least individual steps b) to d3) are repeated several times, preferably continuously, during operation or interruptions of the cooling system, such that even small changes in the system characteristic curve can be detected and taken into account when controlling components or actuators.

[0016] The component may be, for example, a pump, a valve, or a spray nozzle within the cooling system.

[0017] The actual characteristic data are at least individual points of an actual operating characteristic curve of a component, which describes the behavior of the component used in operation of the cooling system during the time interval for which the actual operating characteristic curve is obtained. The term "used component" means that the component behaves differently due to signs of use, i.e., deposits or wear, as opposed to the component's new or fault-free state.

[0018] The target characteristic data for at least individual points of the calibrated characteristic curve of the component in a fault-free state are determined during operation of the cooling system, typically at start-up of the cooling system.

[0019] The above-mentioned problem of the present invention is further solved by a computer program product according to patent claim 9 and a cooling system according to claim 10. The advantages of this solution correspond to the advantages mentioned above for the above-mentioned method.

[0020] A computer program product is a physically salable software product that contains software code sections as a program.

[0021] This specification is accompanied by a total of five figures. [Brief explanation of the drawings]

[0022] [Figure 1] This is the coolant side of the cooling system. [Figure 2] 3 is a control portion of the cooling system according to the first embodiment. [Figure 3] 1 is a comparison of calibrated and operating characteristic curves of cooling system components. [Figure 4] 4 is a control portion of a cooling system of the present invention according to a second embodiment. [Figure 5] 10 is a control portion of a cooling system of the present invention according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0023] In the following, the invention will be explained in detail by way of example with reference to the above-mentioned drawings, in which identical technical elements are provided with the same reference symbols.

[0024] FIG. 1 shows the coolant side of a cooling system 100 of the present invention. This cooling system is used to cool a rolled product 20 in a rolling mill. For this purpose, the cooling system preferably includes a supply device 10 for supplying coolant at a predetermined pressure to cool the rolled product. The coolant is introduced from the supply device 10 via at least one line 12 to an applicator 4, e.g., a cooling beam equipped with spray nozzles, for applying the coolant to the rolled product 20. A component 3, e.g., a pump or valve, is typically installed in the line 12 to control or adjust the pressure of the volumetric flow for supplying the coolant to the applicator 4. Additionally, a pressure gauge or volumetric flow meter 5 is installed in the line to determine the current actual pressure or actual volumetric flow rate of the coolant.

[0025] The horizontal arrow pointing to the left in FIG. 1 indicates the direction of coolant flow from the supply device 10 to the applicator device 4 .

[0026] FIG. 2 shows the control part of the cooling system 100. It can be seen that the component 3 functions here as an actuator, for example, in a control circuit. In addition to the component 3, the control circuit also includes a setpoint setting device 1 in the form of a cooling model for setting a setpoint pressure or a setpoint volumetric flow rate at which the coolant must be supplied to the application device 4 and applied to the rolled product 20. The control circuit provides for these setpoints to be compared with the actual values ​​of pressure or volumetric flow rate, determined by a pressure or volumetric flow meter 5, by forming a difference to determine a control deviation, which is input to the controller 2. The controller 2 itself is used to output a control variable to a component 3 connected downstream of the controller 2, in particular a pump. The controller 2 is configured to form a control variable such that the current actual pressure or actual volumetric flow rate of the coolant is adapted or adjusted to a predetermined setpoint pressure or setpoint volumetric flow rate.

[0027] As an alternative to the control circuit shown in Figure 2, the coolant can also be regulated only to a predetermined target pressure or target volumetric flow rate within the range of control. In contrast to a control loop, in the controlled case there is no feedback of the actual pressure or actual volumetric flow rate of the coolant in line 12 as determined by a pressure gauge or volumetric flow meter 5. Therefore, adaptation of the magnitude of the controlled quantity is typically not based on the deviation between the target data and the actual data, but rather on empirical values.

[0028] Experience has shown that components 3 do not remain in their original fault-free condition during the component's lifetime in cooling system 100, but rather are subject to contamination, deposits, corrosion and / or wear, meaning that a component in a used condition will no longer exhibit the same control behavior as a component in a new or fault-free condition.

[0029] Figure 3 illustrates this different behavior of a component by comparing a calibrated characteristic curve with an operating characteristic curve for the same component. For both characteristic curves, the flow rate Q is plotted against the valve opening y of the component. In this case, the calibrated characteristic curve represents the target characteristic curve, which indicates the optimal behavior of the component 3 in a new or fault-free state. In contrast, the operating characteristic curve for the same component shown in Figure 3 is somewhat flatter. Unlike the calibrated characteristic curve, the operating characteristic curve represents the actual behavior of the same component in use after a certain operating time or period of use. At least individual points on the calibrated characteristic curve will hereinafter also be referred to as target characteristic data, while at least individual points on the operating characteristic curve will hereinafter also be referred to as actual characteristic data. The operating characteristic curve will also be referred to as the actual operating characteristic curve. The vertical difference in the graph of Figure 3, i.e., the difference in the component's flow rate at the same valve opening position between the calibrated characteristic curve and the operating characteristic curve, i.e., the difference between the new and used state, will hereinafter be referred to as the characteristic data deviation Δ.

[0030] In order to take into account these changed setting behaviors of the components, the present invention contemplates that the cooling system 100 has a device 3a for capturing the current opening degree y of each of the components 3 and a characteristic data capturing device 6 for determining at least individual points of the actual operating characteristic curve of the component 3.

[0031] As explained in Figure 3, the operating characteristic curve can be expressed as, for example, the actual flow rate Q or the actual volumetric flow rate V · 3 is a graph plotting the actual pressure of the coolant against the opening y of the component 3. Alternatively, for example, the actual pressure of the coolant can be plotted against the opening of the component. The characteristic data acquisition device 6 is configured to generate at least individual points of this actual operating characteristic curve of the component as actual characteristic data based on the actual pressure or the actual volume flow rate acquired by the measuring device 5 and the respectively associated acquired opening of the component.

[0032] The present invention further contemplates that the cooling system 100 includes a comparison / evaluation device 7 for comparing the actual characteristic data from the characteristic data acquisition device 6 with target characteristic data representing at least individual points of the component's calibrated characteristic curve. The Q(y) graphs in FIGS. 2, 4, and 5 show the target characteristic data or the calibrated characteristic curve, respectively. This comparison allows the characteristic data deviation Δ, plotted in FIG. 3, to be determined, and whether this characteristic data deviation exceeds a predetermined threshold can be evaluated. Finally, the cooling system according to the present invention includes an output device 8 for outputting an indication or warning to an operator or a reporting system of the cooling system 100 if the characteristic data deviation Δ exceeds a threshold. Alternatively, or in addition to this information, an error derived from the characteristic data deviation Δ can be output.

[0033] Advantageously, the characteristic data deviation Δ is not only determined but also appropriately used to regulate or control the component 3. This is achieved, for example, by applying a correction value calculated from the characteristic data deviation, or disturbance variable, to the control device or controller 2, as described above, representing the deviating behavior of the used component 3 compared to a new, fault-free component. This disturbance-variable switching 9 enables the control device or controller 2 to determine and output a corrected manipulated variable to the component 3. Unlike the original, uncorrected manipulated variable, the corrected manipulated variable takes into account the used state of the component and the changed setting behavior resulting from that used state. In this way, a more accurate setting or adjustment of the actual pressure or actual volumetric flow rate of the coolant to a corresponding given target value is possible.

[0034] Alternatively or additionally, the characteristic data deviation Δ or a correction value calculated from this characteristic data deviation Δ can also be output as a disturbance variable to the setpoint setting device 1. In this case, the setpoint setting device 1 also takes into account the setting behavior of the component 3, which has been changed due to use, when calculating the setpoint pressure or setpoint volume flow rate to be output to the control device or controller 2. These two variants are shown in Figures 4 and 5. Figure 4 shows variable switching of the disturbance variable for both the control device or controller 2 and the setpoint setting device 1. Figure 5 shows variable disturbance switching for the setpoint setting device 1 only.

[0035] The characteristic data acquisition device 6 is not only suitable for determining at least individual points of the actual operating characteristic curve of the component 3 in use. Rather, the characteristic data acquisition device 6 is equally suitable for determining at least individual points of the calibrated characteristic curve of the component, i.e., when the component 3 operates in a new or fault-free state, preferably in a new or fault-free system environment. These at least individual points of the calibrated characteristic curve, also referred to as target characteristic data, are typically measured at the start of operation of the cooling system, in particular of the component. [Explanation of symbols]

[0036] 1 Target value setting device 2 Controller, control device 3. Components (= actuators), especially valves, pumps, spray nozzles 3a Grasping devices for component opening, volume flow rate and pressure 4. Application equipment, especially spray nozzles 5. Measuring devices (pressure and / or volume flow) 6. Devices for grasping characteristic data curves or operating characteristic curves of components 7 Comparative evaluation device 8 Output Devices 9. Disturbance-variable switching device Δ Characteristic data deviation 10. Coolant supply device 12 lines 20 Rolled products 100 Cooling System Δ Characteristic data deviation y Valve opening Q flow rate

Claims

1. A method for monitoring a component (3) of a cooling system (100) in a rolling mill, comprising the steps of: The cooling system (100) including the component (3) is used to apply a coolant to the rolled product (20) to be cooled, The method comprises the steps of: a) setting target characteristic data for a component (3), the target characteristic data representing a calibrated behavior of the component (3) in a fault-free state during operation of the cooling system (100); b) determining actual characteristic data of the component (3) during and / or after the use period of the component (3); c) comparing the actual characteristic data with the target characteristic data of the component (3) and determining possible characteristic data deviations (Δ) indicative of a malfunction of the component (3); d) taking measures to minimize the characteristic data deviation (Δ) if the characteristic data deviation (Δ) exceeds a predetermined threshold; A method comprising:

2. According to step d) of the method, d1) issuing a warning to an operator or a reporting system of the cooling system (100) to inspect the component (3); 2. The method of claim 1, comprising:

3. The cooling system (100) comprises a control device or controller (2) for outputting a manipulated variable to a component (3) connected downstream of the control device or controller as an actuator for setting or adjusting an actual pressure or an actual volumetric flow rate at which a coolant is applied to the rolled product (20) to be cooled to a predetermined target pressure or target volumetric flow rate, when adjusting based on at least a characteristic data deviation (Δ) representing a difference between target characteristic data and actual characteristic data; According to step d) of the method, d2) variable switching of the characteristic data deviation (Δ) or a correction value calculated from the characteristic data deviation (Δ) as a disturbance variable in the sense of a disturbance variable switching (9) to the control device or controller (2) in order to determine a corrected manipulated variable and output the corrected manipulated variable at the output of the control device or controller (2) to the component (3); 3. The method according to claim 1, further comprising:

4. The cooling system (100) comprises a control device or controller (2) having an upstream target value setting device (1) and a downstream actuator element (3) for setting or regulating the pressure or volumetric flow rate at which the coolant is applied to the rolled product (20) to be cooled, According to step d) of the method, d3) variable switching of the characteristic data deviation (Δ) or a correction value calculated from the characteristic data deviation (Δ) as a disturbance variable in the sense of a disturbance variable switching (9) to the setpoint setting device (1) in order to adapt a setpoint for the control device or controller (2); The method according to any one of claims 1 to 3, characterized in that it comprises:

5. At least individual steps b) to d3) are repeated several times, preferably consecutively, during operation or interruption of the cooling system (100), 5. The method according to claim 1, wherein the first and second electrodes are connected to a first electrode.

6. The component (3) is a pump, a valve, or a spray nozzle.

6. The method according to any one of claims 1 to 5.

7. the actual characteristic data being at least individual points of an actual operating characteristic curve of the component (3), the actual operating characteristic curve describing the behavior of the component (3) used during operation of the cooling system (100) during a time interval during which the actual operating characteristic curve is captured; 7. The method according to any one of claims 1 to 6.

8. the target characteristic data are at least individual points of a calibrated characteristic curve (10) of the component (3), the actual operating characteristic curve describing the behavior of a new, fault-free component (3) used in operation of the cooling system (100), preferably new and fault-free, during a time interval during which the actual operating characteristic curve is captured; 8. The method according to any one of claims 1 to 7.

9. A computer program product comprising software code portions that can be directly loaded into the internal memory of a digital computer and that, when the product is run on the computer, perform the steps according to the method of any one of claims 1 to 8.

10. A cooling system (20) for cooling a rolled product (20) in a rolling mill, comprising: a supply device (10) for providing a coolant for the cooling system (100) at a predetermined pressure; a cooling section comprising at least one application device (4), in particular a spray nozzle, for applying a coolant to the rolled product (20); at least one line (12) for supplying coolant from a supply device to the application device (4); at least one pressure or volume flow meter (5) for determining the actual pressure or actual volume flow rate in the line; a target value setting device (1), for example in the form of a cooling model, for setting a target pressure or a target volumetric flow rate at which the coolant should be applied to the rolled product (20); At least one component (3), such as a pump, a valve and / or a spray nozzle (5) in the line; a control device or controller (2) for outputting a manipulated variable to an actuator connected downstream of the control device or controller in the form of a component (3) for setting or adjusting an actual pressure or an actual volumetric flow rate at which a coolant is applied to the rolled product (20) to be cooled to a predetermined target pressure or target volumetric flow rate, respectively, when adjusting the actual pressure or volumetric flow rate in response to at least a characteristic data deviation (Δ) representing the difference between target characteristic data and actual characteristic data; It is equipped with A grasping device (3a) for the opening degree of the component (3); a characteristic data acquisition device (6) for determining at least individual points of an actual operating characteristic curve of the component (3) according to the actual pressure or actual volume flow rate acquired by the measuring device (5) and the opening degree of the component (3) acquired; a comparison and evaluation device (7) for comparing the actual characteristic data with target characteristic data representing at least individual points of a calibrated characteristic curve of the component (3), determining a characteristic data deviation (Δ), and evaluating whether the characteristic data deviation (Δ) exceeds a predetermined threshold value; A cooling system (100) comprising:

11. an output device (8) for outputting an indication or warning to an operator or a reporting system of the cooling system (100) that the characteristic data deviation (Δ) exceeds a threshold value and / or that the component (3) should be inspected; The cooling system (100) of claim 10.

12. a disturbance variable switching device (9) for variably switching the characteristic data deviation (Δ) or a correction value calculated from the characteristic data deviation (Δ) as a disturbance variable to the control device or controller (2) in order to determine a corrected manipulated variable and output the corrected manipulated variable at the output of the control device or controller (2) to the component (3); 12. Cooling system (100) according to claim 10 or 11.

13. The disturbance variable switching device (9) is further configured to variably switch the characteristic data deviation (Δ) or a correction value calculated from the characteristic data deviation (Δ) as a disturbance variable to a setpoint value setting device (1) for adapting a setpoint pressure or a setpoint volume flow rate for a control device or controller (2). A cooling system (100) according to any one of claims 10 to 12.

14. The characteristic data acquisition device (6) is further configured to acquire a calibrated characteristic curve of the component (3) when the cooling system (100) and the component (3) are in a new state or when there is no fault. A cooling system (100) according to any one of claims 10 to 13.

15. The cooling system is provided and configured to carry out the method according to any one of claims 1 to 8. A cooling system (100) according to any one of claims 10 to 14.

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